A two-dimensional device testing apparatus, assembly method, and electrical performance testing method based on a diamond anvil cell.

Abstract

This application provides a testing device, assembly method, and electrical performance testing method for two-dimensional devices based on a diamond anvil cell, belonging to the field of high-voltage electrical transport measurement technology for two-dimensional materials. The two-dimensional device testing device includes a diamond anvil cell, a metal pad, an insulating part, and a two-dimensional device. The insulating part includes a first insulating part and a second insulating part. Second through holes are formed in the areas corresponding to the first through hole in both the first and second insulating parts. The inner walls of the two second through holes, the upper surface of the lower diamond anvil cell, and the lower surface of the upper diamond anvil cell together form a sample cavity. The two-dimensional device is housed within the sample cavity. The two-dimensional device includes a bottom grid, a first dielectric layer, an in-plane Hall electrode, a two-dimensional material, a second dielectric layer, and a top grid, stacked sequentially. This testing device can simultaneously control the grid voltage and pressure, thereby achieving the measurement of the electromagnetic transport characteristics of the two-dimensional material under the synergistic effect of the grid voltage and pressure.

Description

Technical Field

[0001] This application relates to the field of high voltage electric transport measurement technology for two-dimensional materials, and more specifically, to a two-dimensional device testing device, assembly method, and electrical performance testing method based on a diamond anvil cell. Background Technology

[0002] Pressure, as a "clean" technique for controlling the physical properties of materials, can significantly enhance interlayer coupling at the interface by compressing the interlayer spacing of two-dimensional material heterostructures without introducing impurities, thereby inducing a variety of novel physical phenomena, including exciton modulation. Therefore, using high-pressure technology to enhance interlayer coupling in two-dimensional material heterostructures has become one of the key methods in current materials research. However, current diamond anvil cell-based two-dimensional device testing devices typically only achieve electrical transport measurements under different pressures, failing to form multi-dimensional collaborative testing with pressure, resulting in a relatively limited functionality. Summary of the Invention

[0003] The purpose of this application is to provide a two-dimensional device testing device, assembly method, and electrical performance testing method based on a diamond anvil cell. The testing device has a three-layer electrode system and can simultaneously control the gate voltage and pressure, thereby realizing the measurement of the electromagnetic transport properties of two-dimensional materials (such as IV curves, mobility, threshold voltage, superconducting properties, etc.) under the synergistic effect of gate voltage and pressure.

[0004] The embodiments of this application are implemented as follows: In a first aspect, embodiments of this application provide a two-dimensional device testing apparatus based on a diamond anvil cell, comprising a diamond anvil cell, a metal pad, an insulating portion, and a two-dimensional device. The diamond anvil cell includes a lower diamond anvil cell and a upper diamond anvil cell distributed opposite each other in a vertical direction; the metal pad has a first through-hole and is located between the lower diamond anvil cell and the upper diamond anvil cell; the insulating portion includes a first insulating portion and a second insulating portion, the first insulating portion being accommodated within the first through-hole, and the second insulating portion being located between the lower surface of the metal pad and the upper surface of the lower diamond anvil cell; in the vertical direction, the top of the first insulating portion abuts against the lower surface of the upper diamond anvil cell, and the bottom is connected to the top of the second insulating portion, and the first insulating portion, the second insulating portion, and the first through-hole are connected to the upper diamond anvil cell. A second through hole is provided in the area corresponding to the hole. The inner walls of the two second through holes, the upper surface of the diamond anvil, and the lower surface of the diamond upper anvil together form a sample cavity. The two-dimensional device is housed in the sample cavity. In the vertical direction, the two-dimensional device includes a bottom grid, a first dielectric layer, an in-plane Hall electrode, a two-dimensional material, a second dielectric layer, and a top grid, which are stacked sequentially on the upper surface of the diamond anvil. The bottom grid and the top grid are used to electrically connect with the external grid voltage control system, and the in-plane Hall electrode is used to electrically connect with the external DC transport property measurement system.

[0005] In the above technical solution, the two-dimensional device is supported on the upper surface of a diamond anvil and includes a bottom gate, a first dielectric layer, an in-plane Hall electrode, a two-dimensional material, a second dielectric layer, and a top gate stacked sequentially. The combination of the two-dimensional material and the second dielectric layer constitutes a two-dimensional material heterojunction. The in-plane Hall electrode is electrically connected to the two-dimensional material, and its contacts are used for electrical connection with an external DC transport property measurement system. The added bottom gate and top gate are used for electrical connection with an external gate voltage regulation system (to increase the gate voltage regulation function). That is, the two-dimensional device in this application embodiment is a three-layer electrode system. Compared with conventional two-dimensional devices (which usually only have a single layer of electrodes such as a standard Hall six-electrode or a van der Berg four-electrode, and this system only has pressure regulation function), the two-dimensional device with a three-layer electrode system provided in this application embodiment has gate voltage regulation function on the basis of pressure regulation. Thus, the electromagnetic transport properties of the two-dimensional material (such as IV curve, mobility, threshold voltage, superconducting properties, etc.) can be measured under the synergistic effect of gate voltage and pressure. That is, it can give the two-dimensional device testing device a more powerful testing function.

[0006] In some alternative implementations, the side of the bottom gate facing away from the first dielectric layer is connected to the upper surface of the diamond anvil.

[0007] In the above technical solution, the bottom grid is directly connected to the diamond anvil, that is, the entire two-dimensional device and the diamond anvil are an integral structure. This type of two-dimensional device has the advantages of high structural stability, high testing accuracy and high success rate.

[0008] In some alternative embodiments, in the vertical direction, the diamond upper anvil is a rotating body that is larger at the top and smaller at the bottom, the lower surface of the diamond upper anvil is a circular plane with a diameter of 280 μm to 320 μm, the diamond lower anvil is a cube whose orthographic projection overlaps everywhere, and the length and width of the upper surface of the diamond lower anvil are both 2.5 mm to 3.5 mm, and the vertical dimension is 2 mm to 3 mm.

[0009] In the above technical solution, when the diamond upper anvil and the diamond lower anvil are respectively configured as described above, limiting their size parameters to the above ranges can enable the diamond anvil to have excellent pressure resistance as a whole, thereby enabling accurate testing of various electrical properties of two-dimensional devices within a large pressure range.

[0010] In some alternative implementations, the four edges of the metal gasket extend beyond the diamond anvil, and the lower surface of the extended area of ​​the metal gasket is provided with insulating adhesive.

[0011] In the above technical solution, the four edges of the metal pad extend beyond the diamond anvil and an insulating adhesive is provided on the lower surface of the extended area. This arrangement can effectively isolate the metal pad from the areas where various electrodes in the two-dimensional device located on the diamond anvil may come into contact, thereby reducing the risk of internal short circuit.

[0012] In some alternative implementations, the geometric center of the first through-hole coincides with the geometric center of both the upper and lower diamond anvils.

[0013] In the above technical solution, the geometric centers of the first through hole, the upper diamond anvil, and the lower diamond anvil all coincide, giving the entire two-dimensional device testing device the advantages of high structural stability and a relatively regular overall structure.

[0014] In some alternative implementations, the geometric center of the second through hole coincides with the geometric center of the first through hole.

[0015] In the above technical solution, the geometric centers of the first through hole and the second through hole coincide, which gives the entire two-dimensional device testing device the advantages of high structural stability and relatively regular overall structure.

[0016] In some alternative implementations, the insulation is made of a mixture of aluminum oxide and epoxy resin.

[0017] In the above technical solution, the insulating part is made of a mixture of aluminum oxide and epoxy resin, which makes the insulating part not only have excellent pressure resistance but also transparent like diamond, thus facilitating real-time observation of the status of various functional devices in the two-dimensional device during the test.

[0018] In some alternative implementations, the mass ratio of alumina to epoxy resin is (2~5):1.

[0019] In the above technical solution, the mass ratio of the two is limited to the above range so that the inner wall of the sample cavity has a relatively dense, smooth and flat characteristic. This can reduce the interference of the insulating material on the pressure transmission medium in the sample cavity (which needs to be filled into the sample cavity together with the ruby ​​before subsequent testing) during the testing process. At the same time, it can also reduce the probability of the insulation chipping affecting the two-dimensional device, thereby improving the detection accuracy.

[0020] In some alternative implementations, the vertical dimension of the sample chamber is 15 μm to 20 μm.

[0021] In the above technical solution, the vertical dimension of the sample chamber is limited to the above range, that is, the sum of the dimensions of the first insulating part and the second insulating part corresponding to the first through hole is limited to the above range, so that the sample chamber has the advantage of not being easily deformed under high pressure and being able to effectively maintain hydrostatic pressure.

[0022] Secondly, embodiments of this application provide an assembly method for a two-dimensional device testing apparatus as provided in the first aspect embodiment, comprising the following steps: A diamond anvil connected to a two-dimensional device is provided. Along the thickness direction of the diamond anvil, the two-dimensional device includes a bottom gate, a first dielectric layer, an in-plane Hall electrode, a two-dimensional material, a second dielectric layer, and a top gate, stacked sequentially. The side of the bottom gate facing away from the first dielectric layer is connected to the upper surface of the diamond anvil. A metal gasket with an insulating portion is also provided. Along the thickness direction of the metal gasket, the metal gasket has a first through-hole. The insulating portion includes a first insulating portion and a second insulating portion. The first insulating portion is accommodated within the first through-hole, and its two ends are flush with the two opposing surfaces of the metal gasket. The second insulating part is located on one side surface of the metal pad and abuts against the end corresponding to the first insulating part. The first insulating part and the area corresponding to the first through hole of the second insulating part are both provided with second through holes. The diamond lower anvil connected to the two-dimensional device, the metal pad with the insulating part and the diamond upper anvil are assembled so that the two-dimensional device is accommodated in the sample cavity formed by the inner walls of the two second through holes, the upper surface of the diamond lower anvil and the lower surface of the diamond upper anvil, and the second insulating part is located between the metal pad and the upper surface of the diamond lower anvil.

[0023] In the above technical solution, a diamond anvil connected to a two-dimensional device and a metal gasket with an insulating part are first provided, and then assembled together with a diamond upper anvil to obtain the two-dimensional device testing device provided in the first aspect embodiment. Since the two-dimensional device has a three-layer electrode system, the electromagnetic transport characteristics of the two-dimensional material (such as IV curve, mobility, threshold voltage, superconducting characteristics, etc.) can be measured under the synergistic effect of gate voltage and pressure, that is, the two-dimensional device testing device can be endowed with more powerful testing functions.

[0024] In some alternative embodiments, the fabrication steps of the diamond anvil cell with the two-dimensional device include: forming a bottom gate in situ on its upper surface using photolithography and magnetron sputtering in the thickness direction of the diamond anvil cell; forming a first dielectric layer on the bottom gate using mechanical lift-off and dry transfer techniques; forming an in-plane Hall electrode on the first dielectric layer using photolithography and magnetron sputtering; fabricating a two-dimensional material and a second dielectric layer on the in-plane Hall electrode using mechanical lift-off and dry transfer techniques; and forming a top gate on the second dielectric layer using photolithography and magnetron sputtering.

[0025] In the above technical solution, the bottom grid is grown directly in situ on the upper surface of the diamond anvil using photolithography and magnetron sputtering techniques. Then, subsequent functional devices are fabricated in sequence. In other words, the entire two-dimensional device is fabricated directly in situ on the diamond anvil. The two-dimensional device prepared in this way has the advantages of high cleanliness, good structural integrity, and a relatively strong bond with diamond, which can effectively improve the testing accuracy and success rate.

[0026] In some alternative implementations, the bottom grid is made of platinum.

[0027] In the above technical solution, platinum metal is selected as the material for the bottom grid, which makes the prepared bottom grid have a high interfacial adhesion to the diamond anvil, effectively reducing the risk of the bottom grid breaking due to stress and other reasons during subsequent high-voltage testing.

[0028] In some alternative implementations, the bottom grid is located at the geometric center of the diamond undercut anvil.

[0029] In the above technical solution, when the bottom gate is grown in situ on the upper surface of the diamond anvil using photolithography and magnetron sputtering, the photoresist thickness in the geometric center region of the diamond anvil is more uniform. This region is used as the preparation area for the bottom gate so that a bottom gate with a more uniform thickness can be prepared in the future. This can also reduce the risk of the bottom gate breaking due to stress and other reasons during the subsequent high-voltage test to a certain extent.

[0030] In some alternative embodiments, the diamond anvil is a cube with overlapping orthographic projections everywhere, and the length and width of the upper surface of the diamond anvil are both 2.5 mm to 3.5 mm, and the thickness is 2 mm to 3 mm.

[0031] In the above technical solution, a regular cubic shape is selected as the diamond anvil (i.e. the growth substrate of two-dimensional devices), and its length, width and thickness are limited to the above range. On the one hand, this can improve the success rate of two-dimensional device fabrication, and on the other hand, it can make the diamond anvil have better pressure resistance.

[0032] In some alternative embodiments, prior to the step of forming the bottom grid, a step of pretreating the diamond undercut anvil is included, the pretreating step comprising: treating the diamond undercut anvil in a mixed acid at 180°C to 220°C for 1 h to 3 h, wherein the mixed acid includes concentrated sulfuric acid, concentrated nitric acid and perchloric acid.

[0033] In the above technical solution, the diamond anvil pretreatment according to the above process can effectively remove conductive impurities (such as various metal ions, carbon-based contaminants, etc.) on its surface while effectively protecting the diamond structure, thereby improving its insulation performance.

[0034] In some alternative embodiments, the volume ratio of concentrated sulfuric acid, concentrated nitric acid, and perchloric acid is (0.8~1.2):(0.8~1.2):(0.8~1.2).

[0035] In the above technical solution, concentrated sulfuric acid, concentrated nitric acid and perchloric acid are prepared according to the above volume ratio, which can improve the insulation of the diamond undercut anvil after pretreatment.

[0036] In some alternative embodiments, the mass fraction of concentrated sulfuric acid is 95% to 100%, the mass fraction of concentrated nitric acid is 65% to 75%, and the mass fraction of perchloric acid is 65% to 75%.

[0037] In the above technical solution, the mass fractions of the three acids are limited to the above range, which can better improve the insulation of the diamond undercut anvil after pretreatment.

[0038] In some alternative embodiments, the preparation steps of the metal gasket with insulating portions include: performing a first pressing treatment on the metal gasket using a diamond anvil cell to form a groove on the side of the metal gasket near the diamond anvil cell; drilling a hole in the groove using laser drilling technology to form a first through hole in the groove; applying the material for forming the insulating portion to the side of the metal gasket away from the diamond anvil cell and into the first through hole; then performing a second pressing treatment on the metal gasket using a diamond anvil cell to form a first insulating portion in the first through hole and a second insulating portion on the side of the metal gasket away from the diamond anvil cell; and then drilling holes in the first insulating portion and the second insulating portion corresponding to the first through hole using laser drilling technology to form two connected second through holes.

[0039] By following the above process, an insulating part with good density and a strong bond with the metal gasket can be prepared. At the same time, the first insulating part and the second insulating part are formed simultaneously, which also has the advantage of simple and easy preparation process.

[0040] In some alternative implementations, the first pressing process includes multiple pressings at a pressure of 10 GPa to 15 GPa.

[0041] In the above technical solution, the pressing process is repeated multiple times using the aforementioned pressure, which can effectively protect the diamond during the pre-pressing process to form the groove.

[0042] In some alternative embodiments, the raw material forming the insulating part is a mixture of alumina and epoxy resin adhesive, and the mass ratio of alumina to epoxy resin adhesive is (2~5):1.

[0043] In the above technical solution, the insulating part is made of a mixture of alumina and epoxy resin, and the mass ratio of the two is limited to the above range. This makes the prepared sample cavity have a relatively dense, smooth and flat inner wall, thereby reducing the interference of the insulating material on the pressure transmission medium in the sample cavity (which needs to be filled into the sample cavity together with the ruby ​​before subsequent testing) during the test, so as to improve the detection accuracy.

[0044] In some alternative implementations, the pressure during the second pressing step is 18 GPa to 20 GPa.

[0045] In the above technical solution, controlling the pressure during the insulation formation process within the aforementioned range enables the formed insulation to have superior density, thereby effectively reducing the risk of deformation during subsequent high-voltage testing and improving the test success rate.

[0046] Thirdly, embodiments of this application provide a method for testing the electrical performance of a two-dimensional device, using the two-dimensional device testing apparatus provided in the first aspect embodiment, including the following steps: The sample chamber is filled with a pressure-transmitting medium and ruby; the bottom gate and top gate are electrically connected to the external gate voltage control system, respectively; the in-plane Hall electrode is electrically connected to the external DC transport property measurement system to test the electrical performance of the two-dimensional device under different gate voltages and different pressures.

[0047] In the above technical solution, by conducting tests according to the above steps, the electromagnetic transport properties of two-dimensional materials (such as IV curves, mobility, threshold voltage, superconducting properties, etc.) can be measured under the combined effect of gate voltage and pressure. Attached Figure Description

[0048] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0049] Figure 1 This is a schematic diagram of the structure of a two-dimensional device testing device provided in an embodiment of this application; Figure 2 for Figure 1 A magnified view of a section at point A in the middle; Figure 3 This is a schematic diagram of the structure of a metal gasket with an insulating part provided in an embodiment of this application; Figure 4A process flow diagram of an assembly method for a two-dimensional device testing apparatus provided in this application embodiment; Figure 5 The graph shows the measurement results of quantum oscillation and quantum Hall effect of graphene under different pressures and gate voltages provided in the embodiments of this application.

[0050] Icons: 10 - Two-dimensional device testing device; 100 - Diamond anvil; 110 - Diamond lower anvil; 120 - Diamond upper anvil; 200 - Metal pad; 210 - First through hole; 220 - Insulating adhesive; 300 - Insulating part; 310 - First insulating part; 320 - Second insulating part; 330 - Second through hole; 400 - Two-dimensional device; 410 - Bottom gate; 420 - First dielectric layer; 430 - In-plane Hall electrode; 440 - Two-dimensional material; 450 - Second dielectric layer; 460 - Top gate; a - Vertical direction. Detailed Implementation

[0051] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0052] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0053] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0054] In the description of this application, it should be noted that the terms "center," "upper," "lower," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product is in use. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. In addition, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0055] Furthermore, terms such as "horizontal," "vertical," and "sag" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0056] In the description of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "set up," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0057] The following provides a detailed description of a two-dimensional device testing apparatus, assembly method, and electrical performance testing method based on a diamond anvil cell.

[0058] See Figure 1 , Figure 2 and Figure 3 In a first aspect, embodiments of this application provide a two-dimensional device testing apparatus 10 based on a diamond anvil cell 100, comprising a diamond anvil cell 100, a metal pad 200, an insulating portion 300, and a two-dimensional device 400. The diamond anvil cell 100 includes a lower diamond anvil cell 110 and an upper diamond anvil cell 120 distributed opposite to each other along a vertical direction a; the metal pad 200 has a first through-hole 210 and is located between the lower diamond anvil cell 110 and the upper diamond anvil cell 120; the insulating portion 300 includes a first insulating portion 310 and a second insulating portion 320, the first insulating portion 310 being accommodated within the first through-hole 210, and the second insulating portion 320 being located between the lower surface of the metal pad 200 and the upper surface of the lower diamond anvil cell 110; in the vertical direction a, the top of the first insulating portion 310 abuts against the lower surface of the upper diamond anvil cell 120, and the bottom is connected to the top of the second insulating portion 320, and the first insulating portion 310 and the second insulating portion 320 are connected. A second through hole 330 is provided in the area corresponding to the first through hole 210. The inner walls of the two second through holes 330, the upper surface of the diamond anvil 110 and the lower surface of the diamond upper anvil 120 together form a sample cavity. The two-dimensional device 400 is housed in the sample cavity. Along the vertical direction a, the two-dimensional device 400 includes a bottom gate 410, a first dielectric layer 420, an in-plane Hall electrode 430, a two-dimensional material 440, a second dielectric layer 450 and a top gate 460, which are stacked sequentially on the upper surface of the diamond anvil 110. The bottom gate 410 and the top gate 460 are used to electrically connect with the external gate voltage control system, and the in-plane Hall electrode 430 is used to electrically connect with the external DC transport property measurement system.

[0059] In this application, a two-dimensional device 400 is mounted on the upper surface of a diamond anvil 110 and includes a bottom gate 410, a first dielectric layer 420, an in-plane Hall electrode 430, a two-dimensional material 440, a second dielectric layer 450, and a top gate 460 stacked sequentially. The combination of the two-dimensional material 440 and the second dielectric layer 450 forms a two-dimensional material 440 heterojunction. The in-plane Hall electrode 430 is electrically connected to the two-dimensional material 440, and its contacts are used for electrical connection with an external DC transport property measurement system. The added bottom gate 410 and top gate 460 are respectively used for electrical connection with an external gate voltage regulation system (to increase gate voltage regulation function). The two-dimensional device 400 in this embodiment is a three-layer electrode system. Compared with conventional two-dimensional devices 400 (which typically only have a single-layer electrode such as a standard Hall six-electrode or a van der Burg four-electrode that is electrically connected to the two-dimensional material 440, and this system only has pressure regulation function), the two-dimensional device 400 with a three-layer electrode system provided in this embodiment has a gate voltage regulation function in addition to pressure regulation. Thus, the electromagnetic transport characteristics of the two-dimensional material 440 (such as IV curve, mobility, threshold voltage, superconducting characteristics, etc.) can be measured under the synergistic effect of gate voltage and pressure, which can give the two-dimensional device testing device 10 more powerful testing functions.

[0060] See Figure 1 and Figure 2 As an example, the side of the bottom gate 410 facing away from the first dielectric layer 420 is connected to the upper surface of the diamond anvil 110.

[0061] In this embodiment, the bottom grid 410 is directly connected to the diamond anvil 110, that is, the entire two-dimensional device 400 and the diamond anvil 110 are an integral structure. This type of two-dimensional device 400 has the advantages of high structural stability, high testing accuracy and high success rate.

[0062] As an example, the thickness (i.e., the dimension in the vertical direction a) of both the bottom gate 410 and the top gate 460 is 15 nm to 20 nm, for example, but not limited to any point value or any range between 15 nm, 16 nm, 17 nm, 18 nm, 19 nm and 20 nm.

[0063] As an example, the first dielectric layer 420 and the second dielectric layer 450 are both made of hexagonal boron nitride and have a thickness of 20 nm to 50 nm, for example, but not limited to any one of 20 nm, 30 nm, 40 nm and 50 nm or any range between the two.

[0064] See Figure 1As an example, in the vertical direction a, the diamond upper anvil 120 is a solid of revolution with a larger top and a smaller bottom. The lower surface of the diamond upper anvil 120 is a circular plane with a diameter of 280 μm to 320 μm (e.g., but not limited to any one of the diameters of 280 μm, 290 μm, 300 μm, 310 μm, and 320 μm, or any range between two). The diamond lower anvil 110 is a cube whose orthographic projection overlaps everywhere (i.e., a structurally regular cube). The length and width of the upper surface of the diamond lower anvil 110 are both 2.5 mm to 3.5 mm (e.g., but not limited to any one of the diameters of 2.5 mm, 2.8 mm, 3.0 mm, 3.2 mm, and 3.5 mm, or any range between two), and its dimension in the vertical direction a is 2 mm to 3 mm (e.g., but not limited to 2 mm, 2.2 mm, 2.4 mm, 2.6 mm, 2.8 mm, and 3.5 mm). (any one of the point values ​​in mm or any range of values ​​between the two).

[0065] In this embodiment, when the diamond upper anvil 120 and the diamond lower anvil 110 are respectively configured as described above, limiting their size parameters to the above ranges enables the diamond anvil 100 to have a relatively excellent pressure-bearing capacity, thereby enabling precise testing of various electrical properties of the two-dimensional device 400 within a large pressure range.

[0066] See Figure 1 and Figure 3 As an example, the four edges of the metal gasket 200 extend beyond the diamond anvil 110, and the lower surface of the area where the metal gasket 200 extends is provided with insulating adhesive 220.

[0067] In this embodiment, the four edges of the metal pad 200 extend beyond the diamond anvil 110 and an insulating adhesive 220 is provided on the lower surface of the extended area. This arrangement can effectively separate the metal pad 200 from the areas where various electrodes in the two-dimensional device 400 located on the diamond anvil 110 may come into contact, thereby reducing the risk of internal short circuits.

[0068] As an example, the metal gasket 200 is made of beryllium copper and has a thickness of 240 μm to 260 μm, such as, but not limited to, any point value or a range between any two of the thicknesses of 240 μm, 245 μm, 250 μm, 255 μm and 260 μm.

[0069] As an example, the orthographic projection of the metal gasket 200 in the vertical direction a is a square with a side length of 4 mm to 6 mm.

[0070] See Figure 1As an example, the geometric center of the first through hole 210 coincides with the geometric center of the upper diamond anvil 120 and the geometric center of the lower diamond anvil 110.

[0071] In this embodiment, the geometric centers of the first through hole 210, the upper diamond anvil 120, and the lower diamond anvil 110 all coincide, giving the entire two-dimensional device testing device 10 the advantages of high structural stability and a relatively regular overall structure.

[0072] See Figure 1 As an example, the geometric center of the second through hole coincides with the geometric center of the first through hole 210.

[0073] In this embodiment, the geometric centers of the first through hole 210 and the second through hole coincide, which gives the entire two-dimensional device testing device 10 the advantages of high structural stability and relatively regular overall structure.

[0074] As an example, the insulation part 300 is made of a mixture of aluminum oxide and epoxy resin.

[0075] In this embodiment, the insulating part 300 is made of a mixture of aluminum oxide and epoxy resin, which makes the insulating part 300 not only have excellent pressure resistance but also transparent like diamond, thus facilitating real-time observation of the status of various functional devices in the two-dimensional device 400 during the test.

[0076] As an example, the mass ratio of alumina to epoxy resin is (2~5):1, for example, but not limited to any one of the mass ratios of 2:1, 3:1, 4:1 and 5:1 or any range between the two.

[0077] In this embodiment, the mass ratio of the two is limited to the above range so that the inner wall of the sample cavity has a relatively dense, smooth and flat characteristic. This can reduce the interference of the insulating material on the pressure transmission medium in the sample cavity (which needs to be filled into the sample cavity together with the ruby ​​before subsequent testing) during the testing process. At the same time, it can also reduce the probability of the insulating material falling off and affecting the two-dimensional device, thereby improving the detection accuracy.

[0078] As an example, the sample cavity has a dimension of 15 μm to 20 μm in the vertical direction a, for example, but not limited to, any point value or a range between 15 μm, 16 μm, 17 μm, 18 μm, 19 μm and 20 μm.

[0079] In this embodiment, the size of the sample chamber in the vertical direction a is limited to the above-mentioned range, that is, the sum of the sizes of the first insulating part 310 and the second insulating part 320 corresponding to the first through hole 210 is limited to the above-mentioned range, so that the sample chamber has the advantage of not being easily deformed under high pressure and being able to effectively maintain hydrostatic pressure.

[0080] It should be noted that, for the two-dimensional device testing apparatus 10 based on the diamond anvil cell 100, the functional units that are not specifically described or limited can be set according to the conventional selection in the art.

[0081] It should be noted that the type of two-dimensional material 440 is not limited; for example, it can be graphene.

[0082] Secondly, embodiments of this application provide an assembly method for a two-dimensional device testing apparatus as provided in the first aspect embodiment, comprising the following steps: providing a diamond anvil connected to a two-dimensional device; along the thickness direction of the diamond anvil, the two-dimensional device includes a bottom gate, a first dielectric layer, an in-plane Hall electrode, a two-dimensional material, a second dielectric layer, and a top gate sequentially stacked, wherein the side of the bottom gate facing away from the first dielectric layer is connected to the upper surface of the diamond anvil; providing a metal pad with an insulating portion; along the thickness direction of the metal pad, the metal pad has a first through hole; the insulating portion includes a first insulating portion and a second insulating portion, the first insulating portion being accommodated in... The first through hole has two surfaces that are flush with the metal pad at both ends. The second insulating part is located on one side surface of the metal pad and abuts against the end of the first insulating part. The first insulating part and the area corresponding to the first through hole of the second insulating part are both provided with second through holes. The diamond lower anvil connected to the two-dimensional device, the metal pad with the insulating part, and the diamond upper anvil are assembled so that the two-dimensional device is accommodated in the sample cavity formed by the inner walls of the two second through holes, the upper surface of the diamond lower anvil, and the lower surface of the diamond upper anvil. The second insulating part is located between the metal pad and the upper surface of the diamond lower anvil.

[0083] In this application, a diamond lower anvil connected to a two-dimensional device and a metal gasket with an insulating part are first provided, and then assembled together with a diamond upper anvil to obtain the two-dimensional device testing device provided in the first aspect embodiment. Since the two-dimensional device has a three-layer electrode system, the electromagnetic transport properties of the two-dimensional material (such as IV curve, mobility, threshold voltage, superconducting properties, etc.) can be measured under the synergistic effect of gate voltage and pressure, that is, the two-dimensional device testing device can be endowed with more powerful testing functions.

[0084] As an example, the fabrication steps of a diamond anvil cell connected to a two-dimensional device include: forming a bottom gate in situ on the upper surface of the diamond anvil cell using photolithography and magnetron sputtering in the thickness direction; forming a first dielectric layer on the bottom gate using mechanical lift-off and dry transfer techniques; forming an in-plane Hall electrode on the first dielectric layer using photolithography and magnetron sputtering; fabricating a two-dimensional material and a second dielectric layer on the in-plane Hall electrode using mechanical lift-off and dry transfer techniques; and forming a top gate on the second dielectric layer using photolithography and magnetron sputtering.

[0085] In this embodiment, the bottom grid is grown directly in situ on the upper surface of the diamond anvil using photolithography and magnetron sputtering techniques. Then, subsequent functional devices are fabricated sequentially. In other words, the entire two-dimensional device is fabricated directly in situ on the diamond anvil. The two-dimensional device prepared in this way has the advantages of high cleanliness, good structural integrity, and a strong bond with diamond, which can effectively improve the testing accuracy and success rate.

[0086] As an example, the bottom grille is made of platinum.

[0087] In this embodiment, platinum metal is selected as the material for the bottom grid, which results in a high interfacial adhesion between the prepared bottom grid and the diamond anvil, effectively reducing the risk of the bottom grid breaking due to stress or other reasons during subsequent high-voltage testing.

[0088] As an example, the in-plane Hall electrode and the top gate are also made of platinum.

[0089] As an example, the bottom grid is located at the geometric center of the diamond undercut anvil.

[0090] In this embodiment, when the bottom gate is grown in situ on the upper surface of the diamond anvil using photolithography and magnetron sputtering, the photoresist thickness in the geometric center region of the diamond anvil is more uniform. This region is used as the preparation area for the bottom gate so that a bottom gate with a more uniform thickness can be prepared in the future. This can also reduce the risk of the bottom gate breaking due to stress or other reasons during the subsequent high-voltage test to a certain extent.

[0091] As an example, the diamond anvil is a cube with overlapping orthographic projections everywhere, and the length and width of the upper surface of the diamond anvil are 2.5 mm to 3.5 mm and the thickness is 2 mm to 3 mm.

[0092] In this embodiment, a regular cubic shape is selected as the diamond anvil (i.e. the growth substrate of the two-dimensional device), and its length, width and thickness are limited to the above range. On the one hand, this can improve the success rate of fabrication of two-dimensional devices, and on the other hand, it can make the diamond anvil have better pressure resistance.

[0093] As an example, prior to the step of forming the bottom grid, a step of pretreating the diamond undercut anvil is included. The pretreating step includes treating the diamond undercut anvil in a mixed acid at 180°C to 220°C (e.g., but not limited to any one of 180°C, 190°C, 200°C, 210°C, and 220°C, or a range between any two) for 1 h to 3 h (e.g., but not limited to any one of 1 h, 1.5 h, 2 h, 2.5 h, and 3 h, or a range between any two), wherein the mixed acid includes concentrated sulfuric acid, concentrated nitric acid, and perchloric acid.

[0094] In this embodiment, pre-treating the diamond anvil according to the above process can effectively remove conductive impurities (such as various metal ions, carbon-based contaminants, etc.) from its surface while effectively protecting the diamond structure, thereby improving its insulation performance.

[0095] As an example, the volume ratio of concentrated sulfuric acid, concentrated nitric acid, and perchloric acid is (0.8~1.2):(0.8~1.2):(0.8~1.2).

[0096] In this embodiment, concentrated sulfuric acid, concentrated nitric acid, and perchloric acid are prepared in the above volume ratio, which can improve the insulation of the diamond undercut anvil after pretreatment.

[0097] As an example, the mass fraction of concentrated sulfuric acid is 95%~100%, the mass fraction of concentrated nitric acid is 65%~75%, and the mass fraction of perchloric acid is 65%~75%.

[0098] In this embodiment, the mass fractions of the three acids are respectively limited to the above-mentioned ranges, which can better improve the insulation of the diamond anvil after pretreatment.

[0099] It should be noted that the specific fabrication processes for the bottom gate, the first dielectric layer, the in-plane Hall electrode, the two-dimensional material, the second dielectric layer, and the top gate are not limited and can be carried out according to conventional processes in this field.

[0100] As an example, the steps for in-situ formation of the bottom gate using photolithography and magnetron sputtering include: spin-coating LOR3A onto the upper surface of a diamond anvil and baking it at 140°C~180°C; then spin-coating S1805 photoresist and baking it at 110°C~130°C; then exposing the shape of the bottom gate on the anvil surface using a UV lithography machine; then developing it in ZX-238 developer for 25 seconds and rinsing it in pure water for 20 seconds; then placing the hardened diamond anvil (70°C~90°C, 1 min~5 min) into the magnetron sputtering system to prepare the bottom gate. Specifically, the coating chamber is first evacuated to 8×10⁻⁶. -8Torr, then argon gas is introduced until the pressure reaches 9.4 × 10⁻⁶. -4 Torr, and then a platinum target is sputtered onto the upper surface of the diamond undercut anvil at a power of 30 W; then the diamond undercut anvil sputtered with platinum metal is immersed in AR 600-71 to form the bottom grid.

[0101] It should be noted that during the subsequent immersion of the diamond anvil with sputtered platinum metal in AR 600-71, the above-mentioned hard film treatment process facilitates the easy and thorough removal of the adhesive layer.

[0102] As an example, the steps of forming a first dielectric layer on the bottom gate using mechanical peeling and dry transfer techniques include: obtaining a thin layer of hexagonal boron nitride (h-BN) using mechanical peeling; characterizing the thickness of h-BN by color under an optical microscope and AFM; selecting h-BN with a thickness of 20 nm to 50 nm as the first dielectric layer; then heating a PDMS (polydimethylsiloxane) / PC (polycarbonate) composite stamp to 80°C to pick up h-BN of appropriate size and uniform thickness; then heating to 170°C to release h-BN onto the bottom gate and immersing it in chloroform for 20 minutes to remove PC.

[0103] As an example, the steps for fabricating an in-plane Hall electrode using photolithography and magnetron sputtering are the same as those for fabricating a bottom gate.

[0104] As an example, the steps for preparing a two-dimensional material and a second dielectric layer on an in-plane Hall electrode using mechanical exfoliation and dry transfer techniques include: obtaining a thin layer of hexagonal boron nitride (h-BN) and a two-dimensional material using a mechanical exfoliation method; then heating a PDMS (polydimethylsiloxane) / PC (polycarbonate) composite stamp to 80°C and sequentially picking up h-BN and the two-dimensional material (h-BN and the two-dimensional material form a stacked heterojunction), followed by heating to 170°C to release the heterojunction onto the in-plane Hall electrode (wherein the two-dimensional material is in contact with the in-plane Hall electrode) and immersing in chloroform for 20 minutes to remove the PC.

[0105] As an example, the steps for fabricating the fixed gate using photolithography and magnetron sputtering are the same as those for fabricating the bottom gate.

[0106] As an example, the preparation steps of a metal gasket with an insulating portion include: performing a first pressing process on the metal gasket using a diamond anvil cell to form a groove on the side of the metal gasket near the diamond anvil cell; drilling a hole in the groove using laser drilling technology to form a first through hole in the groove; applying a material for forming the insulating portion to the side of the metal gasket away from the diamond anvil cell and into the first through hole; then performing a second pressing process on the metal gasket using a diamond anvil cell to form a first insulating portion in the first through hole and a second insulating portion on the side of the metal gasket away from the diamond anvil cell; and then drilling holes in the first insulating portion and the second insulating portion corresponding to the first through hole using laser drilling technology to form two connected second through holes.

[0107] In this embodiment, by preparing according to the above process, an insulating part with good density and a relatively strong bond with the metal gasket can be prepared. At the same time, the first insulating part and the second insulating part are formed simultaneously, which also has the advantage of simple and easy preparation process.

[0108] As an example, the inner diameter of the first through-hole is 240 μm to 250 μm (e.g., but not limited to any one of 240 μm, 242 μm, 244 μm, 246 μm, 248 μm and 250 μm or any range between two), and the inner diameter of the second through-hole is 150 μm to 180 μm (e.g., but not limited to any one of 150 μm, 160 μm, 170 μm and 180 μm or any range between two).

[0109] As an example, the first pressing process includes: performing multiple pressings with a pressure of 10 GPa to 15 GPa (e.g., but not limited to any one of 10 GPa, 11 GPa, 12 GPa, 13 GPa, 14 GPa and 15 GPa or a range between any two).

[0110] In this embodiment, the pressing process is repeated multiple times using the aforementioned pressure, which can effectively protect the diamond during the pre-pressing process to form the groove.

[0111] As an example, the raw material forming the insulating part is a mixture of aluminum oxide and epoxy resin adhesive, and the mass ratio of aluminum oxide to epoxy resin adhesive is (2~5):1.

[0112] In this embodiment, the insulating material is a mixture of alumina and epoxy resin, and the mass ratio of the two is limited to the above range. This makes the prepared sample cavity have a relatively dense, smooth and flat inner wall, which can reduce the interference of the insulating material on the pressure transmission medium in the sample cavity (which needs to be filled into the sample cavity together with the ruby ​​before subsequent testing) during the test, thereby improving the detection accuracy.

[0113] As an example, in the second pressing step, the pressure is 18 GPa to 20 GPa (e.g., but not limited to any one of 18 GPa, 18.5 GPa, 19 GPa, 19.5 GPa and 20 GPa or any range between two).

[0114] In this embodiment, controlling the pressure during the insulation formation process within the aforementioned range enables the formed insulation to have superior density, thereby effectively reducing the risk of deformation during subsequent high-voltage testing and improving the test success rate.

[0115] As an example, the fabrication steps of the diamond anvil connected to the two-dimensional device and the fabrication steps of the metal gasket with insulating parts are carried out simultaneously.

[0116] In this embodiment, the two steps are performed simultaneously, which has the advantage of high assembly efficiency.

[0117] It should be noted that for process steps not specifically described or limited during assembly, conventional processes in this field can be followed.

[0118] As an example, a process flow diagram of the assembly method for a two-dimensional device testing apparatus can be exemplarily referred to. Figure 4 .

[0119] Thirdly, embodiments of this application provide a method for testing the electrical performance of a two-dimensional device, using a two-dimensional device testing apparatus as provided in the first aspect embodiment, comprising the following steps: filling a sample cavity with a pressure-transmitting medium and ruby; electrically connecting the bottom gate and top gate to an external gate voltage control system respectively; and electrically connecting the in-plane Hall electrode to an external DC transport property measurement system to test the electrical performance of the two-dimensional device under different gate voltages and different pressures.

[0120] In this application, by performing tests according to the above steps, it is possible to measure the electromagnetic transport properties of two-dimensional materials (e.g., IV curves, mobility, threshold voltage, superconducting properties, etc.) under the combined effect of gate voltage and pressure.

[0121] It should be noted that all the devices used in the testing process can be selected and configured in accordance with the conventional methods used in this field.

[0122] The features and performance of this application will be further described in detail below with reference to the embodiments.

[0123] Example 1 This application provides an assembly method for a two-dimensional device testing apparatus, including the following steps: (i) Fabrication of a diamond anvil cell connected to a two-dimensional device Pretreatment: The diamond anvil (a diamond anvil is a cube whose orthographic projection overlaps everywhere, and the length and width of the upper surface of the diamond anvil are both 3 mm, and the vertical dimension is 2.5 mm) was treated in a mixed acid at 200°C for 2 h. The mixed acid included concentrated sulfuric acid (98% by mass), concentrated nitric acid (68% by mass), and perchloric acid (70% by mass) in a volume ratio of 1:1:1.

[0124] Bottom gate fabrication: The pretreated diamond anvil is fixed, then LOR3A is spin-coated onto the upper surface of the diamond anvil and baked at 160°C, followed by S1805 photoresist spin-coating and baking at 120°C. The shape of the bottom gate is then exposed on the anvil surface using UV lithography. After development in ZX-238 developer for 25 seconds, it is rinsed clean by soaking in pure water for 20 seconds. The hardened diamond anvil (80°C, 3 min) is then placed in a magnetron sputtering system to fabricate the bottom gate. Specifically, the coating chamber is first evacuated to 8×10⁻⁶. -8 Torr, then argon gas is introduced until the pressure reaches 9.4 × 10⁻⁶. -4 Torr, and then a 20 nm thick platinum target is sputtered onto the upper surface of the diamond anvil at a power of 30 W; then the diamond anvil sputtered with platinum metal is immersed in AR 600-71 to form the bottom gate.

[0125] Preparation of the first dielectric layer: A thin layer of hexagonal boron nitride (h-BN) was obtained by mechanical exfoliation. The thickness of h-BN was characterized by color under an optical microscope and AFM. A thickness of 30 nm was selected as the first dielectric layer. Then, the h-BN was picked up by heating the "PDMS (polydimethylsiloxane) / PC (polycarbonate) composite stamp" to 80°C. After that, the h-BN was released to the bottom gate by heating to 170°C and then immersed in chloroform for 20 minutes to remove PC.

[0126] In-plane Hall electrode fabrication: An in-plane Hall electrode is formed on the surface of the first dielectric layer using the same process as the bottom gate fabrication.

[0127] Preparation of two-dimensional material and second dielectric layer (also known as heterojunction): Thin layer of hexagonal boron nitride (h-BN) and two-dimensional material (graphene) are obtained by mechanical exfoliation; then, the "PDMS (polydimethylsiloxane) / PC (polycarbonate) composite stamp" is heated to 80°C and h-BN and two-dimensional material are picked up in sequence (h-BN and two-dimensional material form a stacked heterojunction), then heated to 170°C to release the heterojunction onto the in-plane Hall electrode (wherein, the two-dimensional material is in contact with the in-plane Hall electrode) and immersed in chloroform for 20 minutes to remove PC.

[0128] Top gate fabrication: The same process as the bottom gate fabrication is used to form the top gate on the surface of the second dielectric layer.

[0129] (ii) Preparation of metal gaskets with insulating parts A diamond anvil cell (vertically, the upper diamond anvil is a rotating body with a larger upper surface and a smaller lower surface, and its lower surface is a circular plane with a diameter of 300 μm; the lower diamond anvil is a cube with overlapping orthographic projections, and its upper surface has a length and width of 3 mm and a vertical dimension of 2.5 mm) is used to repeatedly press a metal pad (made of beryllium copper, 250 μm thick, and a square with a side length of 5 mm in its orthographic projection) under a pressure of 10 GPa to form a groove on the side of the metal pad near the upper diamond anvil cell; laser drilling is used to drill a hole in the groove to form a first through hole with an inner diameter of 250 μm; a material for forming an insulating part (a mixture of alumina and epoxy resin in a mass ratio of 3:1) is applied to the side of the metal pad away from the upper diamond anvil cell and into the first through hole; then, a diamond anvil cell is pressed at 18 GPa. The metal gasket is subjected to a second pressing process under a pressure of GPa to form a first insulating portion in the first through hole and a second insulating portion on the side of the metal gasket away from the diamond anvil (wherein, the total thickness of the first insulating portion and the second insulating portion corresponding to the area of ​​the first through hole is 18 μm); then, laser drilling technology is used to drill holes in the first insulating portion and the second insulating portion corresponding to the first through hole to form two connected second through holes with an inner diameter of 160 μm.

[0130] (III) Assembly The diamond lower anvil connected to the two-dimensional device, the metal gasket with an insulating part, and the diamond upper anvil are assembled so that the two-dimensional device is accommodated in the sample cavity formed by the inner walls of the two second through holes, the upper surface of the diamond lower anvil, and the lower surface of the diamond upper anvil, and the second insulating part is located between the metal gasket and the upper surface of the diamond lower anvil.

[0131] Experimental example: Measurement of quantum oscillations and quantum Hall effect of graphene under different pressures and gate voltages Test method: The sample chamber is filled with a pressure-transmitting medium and ruby ​​(a high-pressure environment is generated by a diamond anvil extrusion pad, and the experimental pressure is calibrated via the ruby ​​in the sample chamber); the bottom and top gates are electrically connected to the external gate voltage control system (to adjust the gate voltage); the in-plane Hall electrode is electrically connected to the external DC transport property measurement system to test the electrical performance of the two-dimensional device under different gate voltages and pressures; the low temperature and magnetic field are achieved by the Cryomagnetics system from Fesco (specifically 1.6 K and 9 T), the application and reading of current and voltage are achieved by Keithley 6221 and 2182A, and the gate voltage is applied by Keithley 2400; the resistivity is measured based on the standard four-electrode method, with graphene as a single-atom-layer material, and the sample resistivity (ρ) is obtained by the formula (ρ=RW / L), where W is the channel width (m), L is the channel length (m), and R is the channel resistance (Ω) measured by the four-electrode method.

[0132] See Figure 5 It is known that under the conditions of 1.6 K temperature and 9 T magnetic field, Rxx exhibits quantum oscillation with changes in gate voltage, and Rxy exhibits a quantum Hall plateau. Furthermore, graphene continuously undergoes spin and valley degeneracy with increasing pressure. This confirms that the two-dimensional device testing device provided in this application, which is prepared in situ with a diamond anvil cell as a substrate, can measure the electromagnetic transport properties of two-dimensional materials (such as IV curves, mobility, threshold voltage, superconducting properties, etc.) under the synergistic effect of gate voltage and pressure, thus endowing the two-dimensional device testing device with more powerful testing functions.

[0133] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A two-dimensional device testing device based on a diamond anvil cell, characterized in that, include: A diamond anvil cell, comprising a lower diamond anvil cell and an upper diamond anvil cell that are distributed opposite to each other in a vertical direction; A metal gasket having a first through hole and located between the diamond lower anvil and the diamond upper anvil; An insulating portion, comprising a first insulating portion and a second insulating portion, wherein the first insulating portion is accommodated within a first through hole, and the second insulating portion is located between the lower surface of the metal pad and the upper surface of the diamond anvil; in the vertical direction, the top of the first insulating portion abuts against the lower surface of the diamond anvil, and the bottom of the first insulating portion is connected to the top of the second insulating portion, and second insulating portions are provided with second through holes in the areas corresponding to the first through hole, the inner walls of the two second through holes, the upper surface of the diamond anvil, and the lower surface of the diamond anvil together form a sample cavity; A two-dimensional device is housed within the sample cavity. Along the vertical direction, the two-dimensional device comprises a bottom gate, a first dielectric layer, an in-plane Hall electrode, a two-dimensional material, a second dielectric layer, and a top gate, which are sequentially stacked on the upper surface of the diamond anvil. The bottom gate and the top gate are respectively used for electrical connection with an external gate voltage control system, and the in-plane Hall electrode is used for electrical connection with an external DC transport property measurement system.

2. The two-dimensional device testing apparatus according to claim 1, characterized in that, The side of the bottom gate opposite to the first dielectric layer is connected to the upper surface of the diamond anvil.

3. The two-dimensional device testing apparatus according to claim 1, characterized in that, In the vertical direction, the upper diamond anvil is a rotating body that is larger at the top and smaller at the bottom. The lower surface of the upper diamond anvil is a circular plane with a diameter of 280 μm to 320 μm. The lower diamond anvil is a cube whose orthographic projection overlaps everywhere. The length and width of the upper surface of the lower diamond anvil are both 2.5 mm to 3.5 mm, and the dimension in the vertical direction is 2 mm to 3 mm.

4. The two-dimensional device testing apparatus according to claim 3, characterized in that, The four edges of the metal pad extend beyond the diamond anvil, and the lower surface of the extended area of ​​the metal pad is provided with insulating adhesive. Optionally, the geometric center of the first through hole coincides with the geometric center of both the upper diamond anvil and the lower diamond anvil. Optionally, the geometric center of the second through hole coincides with the geometric center of the first through hole.

5. The two-dimensional device testing apparatus according to any one of claims 1 to 4, characterized in that, The insulating part is made of a mixture of aluminum oxide and epoxy resin. Optionally, the mass ratio of the alumina to the epoxy resin adhesive is (2~5):1; Optionally, the sample cavity has a dimension of 15 μm to 20 μm in the vertical direction.

6. An assembly method for a two-dimensional device testing apparatus as described in any one of claims 1 to 5, characterized in that, Includes the following steps: A diamond anvil connected to the two-dimensional device is provided. Along the thickness direction of the diamond anvil, the two-dimensional device includes a bottom gate, a first dielectric layer, an in-plane Hall electrode, a two-dimensional material, a second dielectric layer, and a top gate stacked sequentially. The side of the bottom gate opposite to the first dielectric layer is connected to the upper surface of the diamond anvil. A metal gasket with the insulating portion is provided. Along the thickness direction of the metal gasket, the metal gasket has a first through hole. The insulating portion includes a first insulating portion and a second insulating portion. The first insulating portion is accommodated in the first through hole and its two ends are flush with two opposing surfaces of the metal gasket. The second insulating portion is located on one side surface of the metal gasket and abuts against the end corresponding to the first insulating portion. The areas of the first insulating portion and the second insulating portion corresponding to the first through hole are both provided with second through holes. The diamond lower anvil connected to the two-dimensional device, the metal gasket with the insulating portion, and the diamond upper anvil are assembled such that the two-dimensional device is housed within a sample cavity formed by the inner walls of the two second through holes, the upper surface of the diamond lower anvil, and the lower surface of the diamond upper anvil, and the second insulating portion is located between the metal gasket and the upper surface of the diamond lower anvil.

7. The assembly method of the two-dimensional device testing apparatus according to claim 6, characterized in that, The fabrication steps of the diamond anvil connected to the two-dimensional device include: In the thickness direction of the diamond anvil, a bottom gate is formed in situ on its upper surface using photolithography and magnetron sputtering techniques; A first dielectric layer is formed on the bottom gate using mechanical stripping and dry transfer techniques; An in-plane Hall electrode is formed on the first dielectric layer using photolithography and magnetron sputtering techniques; Two-dimensional materials and a second dielectric layer were prepared on the in-plane Hall electrode using mechanical exfoliation and dry transfer techniques. A top gate is formed on the second dielectric layer using photolithography and magnetron sputtering techniques; Optionally, the bottom grid is made of platinum metal; Optionally, the bottom grid is located at the geometric center of the diamond anvil; Optionally, the diamond anvil is a cube with overlapping orthographic projections everywhere, and the length and width of the upper surface of the diamond anvil are both 2.5 mm to 3.5 mm, and the thickness is 2 mm to 3 mm.

8. The assembly method of the two-dimensional device testing apparatus according to claim 7, characterized in that, Before the step of forming the bottom grid, a step of pretreating the diamond undercut anvil is also included. The pretreating step includes treating the diamond undercut anvil in a mixed acid at 180°C to 220°C for 1 h to 3 h, wherein the mixed acid includes concentrated sulfuric acid, concentrated nitric acid and perchloric acid. Optionally, the volume ratio of the concentrated sulfuric acid, the concentrated nitric acid, and the perchloric acid is (0.8~1.2):(0.8~1.2):(0.8~1.2). Optionally, the concentrated sulfuric acid has a mass fraction of 95% to 100%, the concentrated nitric acid has a mass fraction of 65% to 75%, and the perchloric acid has a mass fraction of 65% to 75%.

9. The assembly method of the two-dimensional device testing apparatus according to claim 6, characterized in that, The preparation steps of the metal gasket having the insulating portion include: The metal pad is first pressed using a diamond anvil cell to form a groove on the side of the metal pad near the diamond anvil cell. Laser drilling technology is used to drill holes in the groove to form a first through hole in the groove; The material for forming an insulating portion is applied to the side of the metal pad away from the diamond anvil and into the first through hole. Then, the metal pad is pressed a second time using a diamond anvil to form the first insulating portion in the first through hole and the second insulating portion on the side of the metal pad away from the diamond anvil. Then, laser drilling technology is used to drill holes in the first insulating part and the second insulating part corresponding to the first through hole to form two connected second through holes; Optionally, the first pressing process includes: performing multiple pressings with a pressure of 10 GPa to 15 GPa; Optionally, the raw material for forming the insulating part is a mixture of alumina and epoxy resin, and the mass ratio of the alumina to the epoxy resin is (2~5):1; Optionally, in the second pressing step, the pressure is 18 GPa to 20 GPa.

10. A method for testing the electrical performance of a two-dimensional device, characterized in that, The testing is performed using the two-dimensional device testing apparatus as described in any one of claims 1 to 5, comprising the following steps: The sample chamber is filled with a pressure-transmitting medium and ruby. The bottom gate and the top gate are electrically connected to an external gate voltage control system, respectively. The in-plane Hall electrode is electrically connected to an external DC transport property measurement system to test the electrical performance of the two-dimensional device under different gate voltages and different pressures.

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